There exists on the market a container for sterilizing baby bottles and nipples with an aqueous hypochlorite solution. This container is adapted for receiving baby bottles and nipples the latter being immersed in the hypochlorite solution for at least 90 min, after which the bottles are rinsed with boiled water to remove the taste from this solution. For obtaining adequate sterilization after 90 min, the hypochlorite concentration in the solution should be 125 ppm. It is difficult to reduce this time by increasing the hypochlorite concentration because the hypochlorite taste will then subsist even after rinsing.
Patent application Ser. No. 81/01863 discloses a machine for washing clothes or dishes fitted with an electrochemical cell for producing a hypochlorite solution of desired concentration aimed at providing a bleaching or whitening action. For this, the hypochlorite solution is introduced into the washing bath at a certain concentration and at a desired moment during the washing cycle.
Experiments have been carried out with freshly prepared aqueous hypochlorite solutions from an electrochemical cell which were introduced at a desired concentration into a bath containing baby bottles immersed therein. These experiments have shown that the action of the aqueous hypochlorite solution freshly prepared with an electrochemical cell is similar to that of the hypochlorite sold for sterilizing baby bottles in containers.
By contrast, bewildering results were noted when baby bottles were treated with the hypochlorite solution during the production when this solution after passing it onto the surfaces to be sterilized, was returned to the electrochemical cell for the production of hypochlorite. The hypochlorite concentration of this solution increases progressively during the carrying out of the method.
Comparative testing, the results of which are given hereinafter showed that the destruction of germs with this embodiment is significantly faster and with lower NaOCl concentrations than by immersing baby bottles in a solution of NaOCl obtained by adding into water a concentrated NaOCl solution produced before using it for sterilization. One might explain this surprising result as deriving from the fact that when one uses the NaOCl during the production thereof he takes advantage of the chlorine produced by the electrochemical process which does not instantaneously and completely recombine to provide NaOCl. Yet, the aseptic action of chlorine is known to decreased after recombination of the latter into hypochlorite. This could be the reason why a much faster effect is observed with a solution of extremely weak concentration of NaOCl.
A system has already been proposed in U.S. Pat. No. 3,819,329 in which a bactericidal solution of relatively low pH containing nascent chlorine practically entirely in the form of hypochlorous acid is generated in an electrochemical cell and thereafter distributed on the surfaces to be sterilized. The solution is therefore produced at the desired concentration in the cell and then is dispensed therefrom. Consequently, the production and the use of the solution are not effected together. Now, comparative tests show that the use of NaCl during its production is very important to increase the efficiency of sterilization; this is not possible in the system proposed by this document.
In document GB-A-No. 2,094,992, objects to be sterilized, for instance contact lenses, are dipped into a physiological solution which is subjected to electrolysis so as to obtain a solution of NaOCl. As the dimensions of contact lenses are very small, no distribution means are comtemplated. Since the volume of the necessary solution is very small, the latter is only provided by using two electrodes directly in the cell. Although such a solution is acceptable because of the very small volume of solution to be provided, it is not acceptable when this volume is significantly larger since, there being no agitation, the Faraday yield rapidly decreases due to an electrode polarization phenomenon.